I think Summer just gave up. With all this polar ice cap melting and climate change, the laid back vibes of summer just gave up. It said, See ya!! I'm outta here. You can keep the crazy seasons, that seems to fit your mood just fine.
For me, I'm fine with summer being gone. I know some people are sad and missing their pool days. But for me, I say see us later summer! Bring on the scarves and sweaters.